My Selectronics SP Pro seems to have bad hair days from time to time where for no reason that I can think of it stops sending power out and instead puts the power into the batteries causing them to go way high and then shut down the system. to make matters worse the sp pro defaults to 85% charge causing the batteries to charge when they are already charged. I try to log in as quick as I can and reset the soc but as quick as I do it the charger raises the voltage again and the cycle begins again. I have reduced the voltage on the charger to stop the voltage rising but it still happens. At the moment I have the system at idle because I put out more power than when it is working. at idle the ac inverter puts out about 2000watts but when the system is running it puts out nothing and instead sends the power to the batteries even though the charger is off. Last time this happened I lowered all voltages so it did not matter if it was in bulk or float it was still low and it seemed to do the trick I also updated the firmware in case that would help and have not had any problems for a few weeks but the problem is back. I hope someone may know why this happens.

zap wrote:My Selectronics SP Pro seems to have bad hair days from time to time where for no reason that I can think of it stops sending power out and instead puts the power into the batteries causing them to go way high....

What make and model is your AC coupled inverter?

Can the SP Pro throttle the AC coupled inverter back to zero or very low output?

Is your system grid connected?

Have heard of an SP Pro with an AC coupled Grid Tied inverter overcharging the batteries if the grid disconnects/goes down. When the grid is there excess generation above house and battery charging demand goes to the grid. If the grid goes down the excess goes to the batteries and battery voltage goes battery destroying high.

APR wrote:Can the SP Pro throttle the AC coupled inverter back to zero or very low output?

There are only certain grid inverters that the SP-pro''s fully support for really smart power output control, however there are work arounds that work with almost any grid type inverter/s when the grid is involved, provided it as been either programmed or implemented.

APR wrote:Have heard of an SP Pro with an AC coupled Grid Tied inverter overcharging the batteries if the grid disconnects/goes down. When the grid is there excess generation above house and battery charging demand goes to the grid. If the grid goes down the excess goes to the batteries and battery voltage goes battery destroying high.

Only if the SP-pro has not been setup properly, does this become an issue, when the grid is involved. When the grid type inverter is one that the SP-Pro is not able to manage they are NOT recommended for off-grid use, although with a lot of messing around it can be done, however frankly by the time all the messing around is done you might as well, have simply used a supported grid type managed inverter instead.

davidg wrote:Only if the SP-pro has not been setup properly, does this become an issue.......

If the SP Pro is set up correctly and using compatible AC connected inverter hardware then it should not be doing what the OP is seeing. There has been more than one SP Pro setup that cooked batteries when panel power was up there and the grid connection was lost.

APR wrote:There has been more than one SP Pro setup that cooked batteries when panel power was up there and the grid connection was lost.

Then the SP-pro has not been setup properly.

I used 4 unmanaged grid inverters on my system for 8 years and had many grid failures not once did I have the battery voltage ever climb over or go overvoltage. The SP-pro and I can't stress this enough must be setup correctly. Only replaced them because one of the inverters grid anti island relay failed open circuit. The others were sure to follow and I was able to replace all 4 with one fronius 8.2kw inverter in their place (scert version)

davidg wrote:The so called stuffing around for ages initially was only a couple hours

Fair enough. Here is the $1M question..... would you recommend Joe Blow take on an off grid SP Pro setup using just any grid tied inverter with the view to using the shut down functionality of the inverter as the control mechanism to control charge going to the battery? Or, would you recommend using an inverter with decent ramped output reduction on voltage rise... and preferably something that Selectronics will actually support by actually answering queries for assistance when things go south for what ever reason?????